In recent years, liquid crystal display devices have been widely used not only as still-image display means (for example, display means in mobile phone terminals, digital cameras, etc.) but also as moving-image display means (for example, display means in home television sets), and there has been an increasing need for improved moving-image visibility of liquid crystal display devices, not to mention improved image quality and increased number of reproducible colors.
The key to improving the moving-image visibility of liquid crystal display devices lies in how a blurred image phenomenon (so-called afterimage phenomenon) attributable to the hold type display unique to liquid crystal display devices is alleviated.
In order to alleviate the afterimage phenomenon mentioned above, there has conventionally been employed signal processing for full screen black display performed each time an image signal of one frame is inputted (so-called black insert).
In conventional liquid crystal display devices, the black insert described above has been achieved by a full-screen black display signal inserted instead of an original image signal only during a predetermined period in one frame by use of display control means (a microcomputer or an LCD (liquid crystal display) driver) that controls driving of a liquid crystal panel (see FIGS. 6A and 6B).
As other conventional arts related to the present invention, various liquid crystal display devices have been disclosed and proposed which perform the above-described black insert not by controlling the driving of a liquid crystal panel but by performing the on-off control of a light source illuminating the liquid crystal panel (see, for example, patent publications 1 to 3).
Patent Publication 1: JP-A-2001-125066
Patent Publication 2: JP-A-2004-301984
Patent Publication 3: JP-A-2002-343596